Communications network traffic monitor system

ABSTRACT

First to N-th circuit interface units  104   1  to  104   N  corresponding to first to N-th circuits  103   1  to  103   N  include an input traffic counter unit  114   1 , etc. and an output traffic counter unit  115   1 , etc. for counting the traffic of input and output. A traffic counter monitor block  123  in a control unit  105  specifies an input traffic counter unit  114  and an output traffic counter unit  115  of two circuits  103  through a switch unit  102  in a specific packet flow, and periodically obtains the count values, based on which the utilization rate, the discard rate, etc. of the corresponding circuit  103  are obtained to monitor the traffic. This makes it possible to monitor packet signal traffic when a plurality of circuits are to be switched without capturing each packet signal.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a traffic monitor system formonitoring traffic in a node of a core network of a communicationsnetwork.

[0003] 2. Description of the Related Art

[0004]FIG. 21 shows an outline of a core network in a communicationsnetwork. A core network 11 is a common carrier network and includes: aplurality of edge nodes 12 ₁, 12 ₂, . . . for connecting (joining orseparating) a plurality of ISPs (Internet Service Providers) that arenot shown in the attached drawings; and several core nodes 13 ₁, 13 ₂, .. . for connecting the plurality of edge nodes 12 ₁, 12 ₂, . . .

[0005] For example, assume that a first communications terminal 14 and asecond communications terminal 15 communicate with each other through anInternet network. In this case, a packet signal transmitted from thefirst communications terminal 14 reaches the first edge node 12 ₁through the ISP, reaches the second edge node 12 ₂ through the firstcore node 13 ₁, then reaches the second communications terminal 15through another ISP. It is obvious that another path can be taken when apacket signal is transmitted from the first communications terminal 14to the second communications terminal 15. For example, after reachingthe first edge node 12 ₁, the packet signal can be transmitted throughsecond core node 13 ₂.

[0006] In a communications network that uses packets, such as theInternet, it may be necessary to guarantee a predetermined communicationspeed by reserving a band for specific communications. To attain this,QOS (Quality Of Service) is utilized as a measurement tool. To guaranteethe QOS for specific communications, it is necessary to monitor how apacket is transmitted through a switch or a node in a network.

[0007] For example, in a conventional system for monitoring a network,equipment for exchanging IP (Internet protocol) packets collects thedata in the packets. Then, the flow of a specific IP packet is obtainedby checking the destination IP address and the source IP address fromamong the collected packets.

[0008] In another conventional system for monitoring the network, theinterface of the system captures IP packets. The extraction unitextracts a source address, a destination address, etc. from the IPheader, transmits them to the analysis unit, and computes the totalvalue of traffic for each path.

[0009] The number of packet signals passing through the core network 11is very large, and the communication speed is as high as severalgigabits/seconds or more. Therefore, when attempting to determine theQOS, it is impossible to individually capture the packet signals passingthrough the core network 11. That is, to designate the path of eachpacket signal in the edge nodes 12 ₁, 12 ₂, . . . and core nodes 13 ₁,13 ₂, . . . in the core network 11, it is necessary to monitor eachpacket at a high speed, and individually store the count value of thepackets for each route, which cannot be realized with the currentresources.

[0010] Therefore, in the conventional technology, the guarantee of theQOS for each user or packet flow is omitted, or the size of the corenetwork 11 is increased so that is not needed.

[0011] However, in the latter case, since the packet communicationsdevelop with a larger capacity at a higher speed, the correspondingfacilities are to be extended with sufficient resources, thereby causingthe problem of a difficult economic system configuration. Furthermore,the performance in each node of the core network 11 cannot be improved.If the guarantee of the QOS is to be offered, the extensibility of thenodes is correspondingly lowered.

SUMMARY OF THE INVENTION

[0012] An object of the present invention is to provide a trafficmonitor system capable of monitoring the traffic of packet signalswithout capturing each packet signal.

[0013] To this end, a traffic monitor system for monitoring the traffic,includes

[0014] a plurality of circuit interface units, each being associatedwith a respective pair of input and outputs for a packet signal;

[0015] a switch unit for connecting a packet signal input into a firstof said circuit interface units to a second of said circuit interfaceunits;

[0016] each of said circuit interface units having an input trafficcount unit for counting input packet signals and an output traffic countunit for counting output packet signals and an input and output circuitdesignation unit for designating a packet flow to be monitored;

[0017] an input traffic counter collection unit for periodicallyobtaining a count value from said input traffic count unit in the packetflow designated by said input and output circuit designation unit;

[0018] an output traffic counter collection unit for periodicallyobtaining a count value from said output traffic count unit in thepacket flow designated by said input and output circuit designationunit; and

[0019] a monitor data storage unit for storing each count value obtainedby said input traffic counter collection unit and output traffic countercollection unit.

[0020] Since in this configuration, a system not capable of capturingeach packet signal can configure an economical communications system byefficiently using the resources. Furthermore, since it is not necessaryto capture each packet signal, the performance of the system can bemaintained with the extensibility successfully reserved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of thepresent invention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawingswherein:

[0022]FIG. 1 is a block diagram showing the configuration of a corenetwork node using a traffic monitor system according to an embodimentof the present invention;

[0023]FIG. 2 shows an-example of a point-to-point packet flow;

[0024]FIG. 3 shows the process of collecting a traffic count accordingto an embodiment of the present invention;

[0025]FIG. 4 shows the configuration of a traffic count table providedin the control unit according to an embodiment of the present invention;

[0026]FIG. 5 is a flowchart of the control of the traffic countermonitor block according to an embodiment of the present invention;

[0027]FIG. 6 shows the contents of the traffic count table at theinitial time point;

[0028]FIG. 7 shows the contents of the traffic count table at theinitial time point;

[0029]FIG. 8 shows the flow/circuit corresponding table according to anembodiment of the present invention;

[0030]FIG. 9 shows a change in the traffic count table by an answer ofthe packet flow management block according to an embodiment of thepresent invention;

[0031]FIG. 10 is a flowchart showing the state of controlling thetraffic count collection block according to an embodiment of the presentinvention;

[0032]FIG. 11 shows the contents of the traffic count table at the timewhen a traffic count is received according to an embodiment of thepresent invention;

[0033]FIG. 12 is a block diagram showing the core network node in avariation of an embodiment of the present invention;

[0034]FIG. 13 shows the process of collecting a discard count in thetraffic monitor system as a variation of an embodiment of the presentinvention;

[0035]FIG. 14 shows the configuration of the input/output trafficdiscard count table provided in the control unit as a variation of anembodiment of the present invention;

[0036]FIG. 15 is a flowchart showing the control of the traffic discardcounter monitor block in a variation of an embodiment of the presentinvention;

[0037]FIG. 16 shows the contents of the traffic discard count table atthe initial time point in a variation of an embodiment of the presentinvention;

[0038]FIG. 17 is a flowchart of the state of controlling the packet flowmanagement block in a variation of an embodiment of the presentinvention;

[0039]FIG. 18 is an explanatory view of a change in the traffic discardcount table by an answer from the packet flow management block shown inFIG. 17;

[0040]FIG. 19 is a flowchart showing the control of the traffic discardcounter collection block in a variation of an embodiment of the presentinvention;

[0041]FIG. 20 shows the contents of the traffic discard count table atthe time point when a traffic discard count is received in a variationof an embodiment of the present invention; and

[0042]FIG. 21 shows the configuration of a core network in aconventional communications network.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0043] A traffic monitor system embodying the present invention will bedescribed with reference to FIG. 1 through FIG. 20.

[0044]FIG. 1 shows a configuration of the core network node using thetraffic monitor system according to an embodiment of the presentinvention. A core network node 101 comprises a switch unit 102 for inputand output and first to N-th circuit interface units 104 ₁ to 104 _(N)corresponding to first to N-th circuits 103 ₁ to 103 _(N). The first toN-th circuit interface units 104 ₁ to 104 _(N) are connected to theswitch unit 102, and to a control unit 105 for controlling operation ofthe system with software. In the first circuit interface unit 104 ₁, apacket identification transfer unit 111 ₁ for identifying andtransferring an input packet, an input packet buffer unit 112 ₁ fortemporarily storing an input packet, an output packet buffer unit 113 ₁for temporarily storing an output packet, an input traffic counter unit114 ₁ for counting the traffic relating to input packets, an outputtraffic counter unit 115 ₁ for counting the traffic relating to anoutput packet, and a circuit interface control unit 116 ₁ for control inthe first circuit interface unit 104 ₁. FIG. 1 practically shows onlythe internal configuration of the first circuit interface unit 104 ₁,but the similar internal configuration is designed for the second toN-th circuit interfaces 104 ₂ to 104 _(N).

[0045] The control unit 105 comprises a CPU (central processing unit)not shown in the attached drawings, and a storage medium for storing acontrol program and various data, and realizes some function blocks bythe CPU executing the control program. According to the presentembodiment, control unit 105 includes a packet flow management block 121for managing a packet flow, a traffic counter collection block 122 forcollecting a traffic counter, and a traffic counter monitor block 123for monitoring a traffic counter.

[0046] In the core network node 101 with the above mentionedconfiguration, for example, the input traffic counter unit 114 ₁ and theoutput traffic counter unit 115 ₁ in the first circuit interface unit104 ₁ have the function of inputting, that is, receiving a packet, andoutputting, that is, transmitting, a packet in the first circuit 103 ₁,and counting the amount of data (number of bytes) in a packet.Therefore, the data in a packet is transmitted to the switch unit 102 ina state in which the respective traffic is grasped by the first to N-thcircuit interface units 104 ₁ to 104 _(N), and output to an outputcircuit. The input traffic counter unit 114 ₁ and output traffic counterunit 115 ₁ are conventional counters, and have not been specificallyprepared for the present embodiments.

[0047] The packet flow management block 121 in the control unit 105 forexercising control by software has the function of management of thecorrespondence between a packet flow and the first to N-th circuits 103₁ to 103 _(N). The traffic counter collection block 122 has the functionof storing and managing a traffic counter collected from the circuitinterface control units 116 ₁ to 116 _(N). The traffic counter monitorblock 123 has the function of storing and managing a traffic counter ina circuit unit corresponding to the packet flow. At an instruction fromthe control unit 105, a specified unit in the first to N-th circuitinterface units 104 ₁ to 104 _(N), notifies control unit 105 of theinput and output traffic count. The traffic counter collection block 122stores traffic counts respectively corresponding to the first to N-thcircuits 103 ₁ to 103 _(N) from the traffic counts reported by the firstto N-th circuit interface units 104 ₁ to 104 _(N).

[0048] The traffic counter monitor block 123 inquires of the packet flowmanagement block 121 about the correspondence between a packet flow andthe first to N-th circuits 103 ₁ to 103 _(N) and refers to thecorrespondence table between the packet flow and the input and outputcircuit not shown in the attached drawings. Then, the correspondence foreach of the input and output circuits 103 of a traffic count isobtained, and the amount of data or the amount of discard of thetransmitted and received packets in the core network node 101 can beobtained. Thus, by associating the count in the unit of input and outputcircuit 103 with a packet flow in the control unit 105, a traffic countcorresponding to the packet flow designated in the core network node 101can be collected and monitored. This process is further described belowin detail.

[0049]FIG. 2 shows an example of a point-to-point packet flow. Assumethat a source address is A, and a destination address is B, and that apacket is input from the first circuit 103 ₁ to the first circuitinterface unit 104 ₁, and the packet is output to the second circuit 103₂ now functioning as an output circuit through the switch unit 102 andthe second circuit interface unit 104 ₂. At this time, as the traffic ofthe packet flow A-B, the first circuit interface unit 104 ₁ collects theinput traffic count counted by the input traffic counter unit 114 ₁ asshown in FIG. 1. Furthermore, the second circuit interface unit 104 ₂collects an output traffic count counted by the output traffic counterunit 115 ₂.

[0050] All packets input into the first circuit interface unit 104 ₁ arenot always output to the second circuit 103 ₂ through the second circuitinterface unit 104 ₂. For example, they can be transmitted to adestination address other than the destination address B through thethird circuit 103 ₃. Furthermore, a packet output from the secondcircuit interface unit 104 ₂ to the second circuit 103 ₂ is not alwaysaddressed to the destination address B. However, the packet flow A-B isnecessarily counted by the input traffic counter unit 114 ₁ of the firstcircuit interface unit 104 ₁, passes through the second circuitinterface unit 104 ₂, and is counted by the output traffic counter unit115 ₂. Therefore, according to the present embodiment, the packet flowA-B is monitored with the count by the input traffic counter unit 114 ₁and the output traffic counter unit 115 ₂, and the utilization rates ofthe first and second circuits 103 ₁ and 103 ₂, etc. taken into account.

[0051]FIG. 3 shows the collecting process of the input (received) andoutput (transmitted) traffic count. When the packet flow A-B ismonitored, the control unit 105 shown in FIG. 1 collects the receptioncount collected and stored by the input traffic counter unit 114 ₁ inthe first circuit interface unit 104 ₁, and collects the transmissioncount collected and stored by the output traffic counter unit 115 ₂ inthe second circuit interface unit 104 ₂.

[0052] Regardless of the collection by the control unit 105, uponreceipt of a packet by the first circuit interface unit 104 ₁ in thefirst circuit 103 ₁, the input traffic counter unit 114 ₁ collects andcounts the packet(step S201). Similarly, when the second circuitinterface unit 104 ₂ outputs the packet, the output traffic counter unit115 ₂ collects and counts the packet (step S202). These count values arecollected respectively by the first or second circuit interface unit 104₁ or 104 ₂ (steps S203 and S204). Thus, the first and second circuitinterface units 104 ₁ and 104 ₂ continue the process of updating andstoring each reception count or transmission count (steps S205 andS206).

[0053] Although not shown in FIG. 3, the first circuit interface unit104 ₁ similarly collects and stores the transmission count, and thesecond circuit interface unit 104 ₂ similarly collects and stores thereception count. However, since the count values are not used inmonitoring the point-to-point packet flow A-B, they are not shown inFIG. 3. Similarly, the third to N-th circuit interface units 104 ₃ to104 _(N) collect and store the reception and transmission count. Sincethey are not used in monitoring the point-to-point packet flow A-B, theyare not shown in FIG. 3.

[0054] When the point-to-point packet flow A-B shown in FIG. 2 ismonitored as indicated by the example, the control unit 105 shown inFIG. 1 requests the first and second circuit interface units 104 ₁ and104 ₂ to report on the count stored in them (steps S207 and S208). Basedon this, the first and second circuit interface units 104 ₁ and 104 ₂report on the counts (steps S209 and S210). Thus, the reception andtransmission counts for monitor of the packet flow A-B in the first andsecond circuit interface units 104 ₁ and 104 ₂ are stored in the controlunit (step S211).

[0055] The collection cycle of the reception and transmission counts setby the control unit 105 for the first and second circuit interface units104 ₁ and 104 ₂ in association with the packet flow A-B is set atintervals at which the counters not shown in the attached drawings butprovided for the input traffic count (reception count) and outputtraffic count (transmission count) in the first and second circuitinterface units 104 ₁ and 104 ₂ corresponding to the first or secondcircuit 103 ₁ or 103 ₂ do not overflow. That is, the control unit 105collects and stores each count from the first and second circuits 103 ₁and 103 ₂ in the cycle set depending on the bit widths of the counters.

[0056]FIG. 4 shows a configuration of a traffic count table 131 providedin the control unit 105. A traffic count table 131 stores any circuit tobe monitored from among the first to N-th circuits 103 ₁ to 103 _(N)using the reception count or transmission count in a table form, and thepredetermined storage area in the above mentioned storage medium isassigned therefor. The reception count refers to a count value of theinput traffic counter unit 114 in the corresponding circuit interfaceunit 104, and the transmission count refers to a count value of theoutput traffic count unit 115 in the corresponding circuit interfaceunit 104.

[0057] Described below are a change with time of the contents of thetraffic count table 131 and the operations of the traffic monitorsystem.

[0058]FIG. 5 shows a flow of the control of the traffic counter monitorblock 123. In the control unit 105 shown in FIG. 1, the traffic countermonitor block 123 outputs a request to the packet flow management block121 for obtaining a circuit corresponding to a traffic monitor flow(step S231). Then, the traffic counter monitor block 123 waits for ananswer designating a circuit from the packet flow management block 121(step S232).

[0059]FIG. 6 shows the contents of the traffic count table at an initialtime. In this example, the case in which a request is issued to monitorthe above mentioned packet flow A-B is described. The traffic counttable 131 is provided in the traffic counter monitor block 123 andcontains at the initial state the input circuit, the capacity, thereception count, the rate, and the utilization rate for the sourceaddress A, and the output circuit, the capacity, the transmission count,the rate, and the utilization rate for the destination address B asunfilled.

[0060]FIG. 7 shows the state of controlling the packet flow managementblock 121. In the packet flow management block 121 shown in FIG. 1, thestate of receiving a request for obtaining a circuit corresponding tothe traffic monitor flow from the traffic counter monitor block 123 ismonitored (step S251), and the flow and the correspondence of thecircuit 103 and its change are monitored (step S252). Therefore, uponreceipt of the request for obtaining a circuit corresponding to thetraffic monitor flow (Y in step S251), the packet flow management block121 designates the circuit for the specified flow, and returns it to thetraffic counter monitor block 123. In this example, since a request todesignate a circuit for the packet flow A-B is issued, the packet flowmanagement block 121 returns an answer (step S253). After the answer,for example, if the route of a packet is changed to solve the problem ofa faulty circuit, etc., the correspondence becomes different. Therefore,if the case occurs (Y in step S252), then, as in the correspondencechange in the flow and the circuit 103, the traffic counter monitorblock 123 is notified of the information (step S254).

[0061]FIG. 8 shows an example of a flow/circuit correspondence table 141stored in the packet flow management block 121. Based on the answer ofthe packet flow management block 121 described above in step S253 shownin FIG. 7, the flow/circuit correspondence table 141 describes thecorrespondence between the addresses and the circuit. From theflow/circuit correspondence table 141, the circuit for the packet flowA-B can be the first circuit 103 ₁ and the second circuit 103 ₂.

[0062]FIG. 9 shows a change in the traffic count table by an answer fromthe packet flow management block described in FIG. 7. In this example,the circuits about the packet flow A-B are the first and second circuit103 ₁ and 103 ₂, the traffic count table 131 describes thecorrespondence between them.

[0063] Back in FIG. 5, when the information designating the circuitabout the packet flow A-B is transmitted from the packet flow managementblock 121 (Y in step S232), the traffic counter monitor block 123specifies a circuit corresponding to a request flow for collecting avalue of a traffic counter for the packet flow management block 121(step S233). In this example, based on the traffic count table 131 shownin FIG. 9 as the corresponding circuit, the first and second circuit 103₁ and 103 ₂ are specified. The traffic counter monitor block 123 awaitsthe traffic count collected by the specified circuits from the trafficcounter collection block 122 (step S234).

[0064]FIG. 10 shows the state of controlling the traffic countercollection block 122. The traffic counter collection block 122 storesand manages the transmission and reception counts of each circuit basedon the collection result of the traffic counter (step S271). When arequest to obtain a traffic count is received from the traffic countermonitor block 123 (Y in step S272), the traffic counter monitor block123 is notified of the traffic count of the specified circuit (stepS273).

[0065] When the traffic counter monitor block 123 obtains a trafficcount of the circuit specified by the traffic counter collection block122 (Y in step S234 shown in FIG. 5), it is reflected on the trafficcount table 131 (step S235).

[0066]FIG. 11 shows a change in the traffic count table by the abovementioned processes. As a result of obtaining the traffic count aboutthe first and second circuits 103 ₁ and 103 ₂ from the traffic countercollection block 122, the traffic count table 131 stores the receptioncount and the transmission count. The collection cycle of thetransmission and reception counts is set to 300 seconds in this example.For example, since the reception count of the first circuit 103 ₁ is 90GB, the reception rate per second is 2.4 Gbps (bits/second). Since thecapacity of the input circuit is 10 Gbps, the utilization rate of thecircuit is 24%.

[0067] On the other hand, since the transmission count of the secondcircuit 103 ₂ is 120 GB, the transmission rate per second is 3.2 Gbps.Since the capacity of the output circuit is 10 Gbps, the utilizationrate of the circuit is 32%.

[0068] Thus, the circuit utilization rate by the packet flow A-B in thefirst and second circuits 103 ₁ and 103 ₂ is at most 24% which is asmaller value between 24% and 32%. There is still room in the circuitutilization rate. Therefore, it is not necessary at present to switchthe packet flow A-B into another circuit. On the other hand, forexample, if the transmission count of the second circuit 103 ₂ is largeand the utilization rate of the circuit is overflowing although thereception count of the first circuit 103 ₁ is the same as presentexample, then the control unit 105 searches for another path throughwhich a packet can be transmitted to the destination address B throughthe circuit 103 other than the second circuit 103 ₂, thereby switchinginto this path to guarantee the QOS.

[0069]FIG. 12 shows a core network node according to a variation of thepresent invention. In the core network node 101A of the variation, theunits also shown in FIG. 1 are assigned the same reference numerals, andthe detailed explanation is omitted here. The core network node 101A isprovided with first to N-th circuit interface units 104 ₁A to 104 _(N)Acorresponding to the first to N-th circuit interface units 104 ₁ to 104_(N) in the above mentioned embodiment. Each of the first to N-thcircuit interface units 104 ₁A to 104 _(N)A is connected to the switchunit 102, and the control unit 105A for controlling operation of thesystem with software. The first circuit interface unit 104 ₁A isprovided with the input traffic discard counter unit 114 ₁A relating tothe input packets to be discarded, and the output traffic discardcounter unit 115 ₁A relating to the output packets to be discarded. Inthis example, only the internal configuration of the first circuitinterface unit 104 ₁A is shown, but the similar internal configurationis designed for the second to N-th circuit interfaces 104 ₂A to 104_(N)A.

[0070] The control unit 105A comprises a storage medium for storing aCPU, a control program, and various types of data although not shown inthe attached drawings, and realizes some function blocks by the CPUexecuting the control program. In this variation, the control unit 105Aincludes the packet flow management block 121 for managing a packetflow, a traffic discard counter collection block 122A for collecting atraffic discard counter, and a traffic discard counter monitor block123A for monitoring the traffic discard counter.

[0071]FIG. 13 corresponds to FIG. 3 shown in the above mentionedembodiments, and shows the process of collecting a discard count in thetraffic monitor system according to the variation. In the control unit105A shown in FIG. 12, the first circuit interface unit 104 ₁Aaccumulates packets in the input packet buffer unit 112 ₁ (step S301),and receives a notification if there is a packet to be discarded (stepS302). The input traffic discard counter unit 114 ₁A stores as an inputdiscard count the number of packets input based on the notification anddiscarded without being output (step S303).

[0072] On the other hand, the second circuit interface unit 104 ₂A inthe point-to-point packet flow shown in FIG. 2 accumulates the packetsto be output to the output packet buffer unit 113 ₁ (step S304). Ifthere is a packet to be discarded, the notification is transmitted tothe second circuit interface unit 104 ₂A (step S305). The second circuitinterface unit 104 ₂ stores the number of packets to be discarded by theoutput traffic discard counter unit 115 ₂A as an output discard count(step S306).

[0073] The control unit 105A requests the first and second circuitinterface units 104 ₁A and 104 ₂A to report on the stored discard countat a predetermined time intervals to monitor the point-to-point packetflow shown in FIG. 2 (steps S307 and S308). Thus, the first and secondcircuit interface units 104 ₁A and 104 ₂A report on these discard counts(steps S309 and S310). Thus, the input and output discard counts aboutthe packet flow A-B in the first and second circuit interface units 104₁A and 104 ₂A are stored in the control unit (step S311).

[0074] The collection cycle of the input and output discard counts setabout the first and second circuit interface units 104 ₁A and 104 ₂A bythe control unit 105A corresponding to the packet flow A-B is determinedsuch that discard counters (not shown in the attached drawings) providedfor the input discard count and the output discard count in the firstand second circuit interface units 104 ₁A and 104 ₂A corresponding tothe first and second circuits 103 ₁ and 103 ₂ cannot overflow. That is,the control unit 105A collects and stores each discard count from thefirst and second circuits 103 ₁ and 103 ₂ in the cycle set depending onthe bit width of the discard counters.

[0075]FIG. 14 shows the configuration of the input/output trafficdiscard count table 321 provided in the control unit 105A. Aninput/output traffic discard count table 321 stores the collectionresult collected by the control unit 105A in a table format, and apredetermined storage area in the above mentioned storage medium isassigned therefor. The input/output traffic discard count table 321stores the input discard count and the output discard count for each ofthe first to N-th circuits 103 ₁ to 103 _(N). Then, the change in thecontents of the input/output traffic discard count table 321 and theoperations of the traffic monitor system are described below further indetail.

[0076]FIG. 15 shows a flow of the control of the traffic discard countermonitor block 123A. In the control unit 105A shown in FIG. 12, thetraffic discard counter monitor block 123A outputs a request to thepacket flow management block 121 for obtaining a circuit correspondingto a discard monitor flow (step S431). Then, the traffic discard countermonitor block 123A waits for an answer designating a circuit from thepacket flow management block 121 (step S432).

[0077]FIG. 16 shows the contents of the traffic discard count table atan initial time. In this example, the case in which a request is issuedto monitor the above mentioned packet flow A-B is described. The trafficdiscard count table 331 is provided in the traffic discard countermonitor block 123A and contains at the initial state the input circuit,the capacity, the reception count, the rate, the utilization rate, thediscard count, and the discard rate for the source address A, and theoutput circuit, the capacity, the transmission count, the rate, theutilization rate, the discard count, and the discard rate for thedestination address B as unfilled.

[0078]FIG. 17 shows the state of controlling the packet flow managementblock 121 in the variation. In the packet flow management block 121shown in FIG. 12, the state of receiving a request for obtaining acircuit corresponding to the traffic discard monitor flow from thetraffic discard counter monitor block 123A is monitored (step S451), andthe flow and the correspondence of the circuit 103 and its change aremonitored (step S452). Therefore, upon receipt of the request forobtaining a circuit corresponding to the traffic discard monitor flow (Yin step S451), the packet flow management block 121 designates thecircuit for the specified flow, and returns it to the traffic discardcounter monitor block 123A. In this example, since a request todesignate a circuit for the packet flow A-B is issued, the packet flowmanagement block 121 returns an answer (step S453) After the answer, forexample, if the route of a packet is changed to solve the problem of afaulty circuit, etc., the correspondence becomes different. Therefore,if the case occurs (Y in step S452), then, as in the correspondencechange in the flow and the circuit 103, the traffic discard countermonitor block 123A is notified of the information (step S454).

[0079] Also in this variation, the packet flow management block 121 isprovided with the flow/circuit correspondence table 141 shown in FIG. 8.Therefore, the packet flow management block 121 returns an answer fromthe flow/circuit correspondence table 141 that the circuits of thepacket flow A-B are the first and second circuits 103 ₁ and 103 ₂.

[0080]FIG. 18 shows a change in the traffic discard count table by ananswer of the packet flow management block by referring to FIG. 17. Inthis example, the circuits of the packet flow A-B are the first andsecond circuits 103 ₁ and 103 ₂. Therefore, the traffic discard counttable 331 describes the correspondence between them.

[0081] Back in FIG. 15, when the information designating the circuitabout the packet flow A-B is transmitted from the packet flow managementblock 121 (Y in step S432), the traffic discard counter monitor block123A specifies a circuit corresponding to a request flow for collectinga value of a traffic discard counter for the packet flow managementblock 121 (step S433). In this example, based on the traffic discardcount table 331 shown in FIG. 18 as the corresponding circuit, the firstand second circuit 103 ₁ and 103 ₂ are specified. The traffic discardcounter monitor block 123A awaits the traffic discard count collected bythe specified circuits from the traffic discard counter collection block122A (step S434).

[0082]FIG. 19 shows the state of controlling the traffic discard countercollection block 122A. The traffic discard counter collection block 122Astores and manages the input and output discard counts of each circuitbased on the collection result of the traffic discard counter (stepS471). When a request to obtain a traffic discard count is received fromthe traffic discard counter monitor block 123A (Y in step S472), thetraffic discard counter monitor block 123A is notified of the trafficdiscard count of the specified circuit (step S473).

[0083] When the traffic discard counter monitor block 123A obtains atraffic count of the circuit specified by the traffic discard countercollection block 122A (Y in step S434 shown in FIG. 5), it is reflectedon the traffic discard count table 331 (step S435).

[0084]FIG. 20 shows a change on the traffic discard count table by theabove mentioned processes. As a result of obtaining the traffic discardcount about the first and second circuits 103 ₁ and 103 ₂ from thetraffic discard counter collection block 122A, the traffic discard counttable 331 stores the input discard count and the output discard count.The collection cycle of the input and output counts is set to 300seconds in this example. For example, since the input (reception)discard count of the first circuit 103 ₁ is 90 GB, the reception rateper second is 2.4 Gbps. Since the capacity of the input circuit is 10Gbps, the utilization rate of the circuit is 24%. Assuming that thediscard count for the input circuit is 0.09 MB, the ratio to thereception count of 90 GB is computed and the discard rate is 10⁻⁶.Similarly, the discard rate for the output circuit is 10⁻⁵. Therefore,as described in the above mentioned embodiments, by referring to thediscard rates, etc. of the circuits 103 ₁ and 103 ₂, a specific packetflow is monitored and a route is to be switched.

[0085] As described above about the embodiments and variations, the corenetwork nodes 101 and the 101A can monitor the circuits by obtainingdata of the utilization rate, the discard rate, etc. of the circuits byspecifying a flow to be monitored, enabling an efficient and delicatemonitor.

[0086] However, in the embodiments and variations, there is shown anexample of monitoring the specific packet flow, and it is obvious thatvarious modes can be taken in monitoring any of the packets. Forexample, the control units 105 and 105A can sequentially monitor onlysome of the requested packet flows, and can sequentially check otherpacket flows not being monitored or controlled by the core network nodes101 and 101A when there is room for the monitor control to perform someother processes. The packet flows on which large transmission orreception count values have been computed, or the packet flows whichhave indicated high utilization rates or discard rates can bespecifically monitored.

[0087] According to the embodiments of the present invention, themonitor of traffic in the core network node has been described indetail, but the present invention can also be applied to the monitor ofother networks having a large number of variations of flows realizedrelative to the resources.

[0088] The present invention can provide the following benefit. In theinvention according to claim 1 and claim 2, a system not capable ofcapturing each packet signal can configure an economical communicationssystem by efficiently using the resources. Furthermore, since it is notnecessary to capture each packet signal, the performance of the systemcan be maintained with the extensibility successfully reserved.

[0089] In the invention according to claim 3, in addition to the countvalues from the input traffic count unit and output traffic count unitaccording to claim 1 of the present invention, the count values from theinput discard traffic count unit and output discard traffic count unitare obtained in a specific packet flow as set forth in claim 2 of thepresent invention. Therefore, the effects of the inventions according toclaims 1 and 2 can be obtained, and the monitor precision can beimproved.

[0090] While this invention has been described with reference to acertain preferred embodiment, it is to be understood that the subjectmatter encompassed by the invention is not limited to this specificembodiment. Instead it is intended for the subject matter of theinvention to include all such alternatives, modifications andequivalents as can be included within the spirit and scope of thefollowing claims.

What is claimed is:
 1. A traffic monitor system for monitoring trafficin a communications network, comprising: a plurality of circuitinterface units, each being associated with a respective pair of inputand outputs for a packet signal; a switch unit for connecting a packetsignal input into a first of said circuit interface units to a second ofsaid circuit interface units; each of said circuit interface unitshaving an input traffic count unit for counting input packet signals andan output traffic count unit for counting output packet signals and aninput and output circuit designation unit for designating a packet flowto be monitored; an input traffic counter collection unit forperiodically obtaining a count value from said input traffic count unitin the packet flow designated by said input and output circuitdesignation unit; an output traffic counter collection unit forperiodically obtaining a count value from said output traffic count unitin the packet flow designated by said input and output circuitdesignation unit; and a monitor data storage unit for storing each countvalue obtained by said input traffic counter collection unit and outputtraffic counter collection unit.
 2. A traffic monitor system formonitoring traffic in a communications network, comprising: a pluralityof circuit interface units, each being associated with a respective pairof input and outputs for a packet signal; a switch unit for connecting apacket signal input into a first of said circuit interface units to asecond of said circuit interface units; each of said circuit interfaceunits having an input discard traffic count unit for counting inputpacket signals that have been discarded and an output discard trafficcount unit for counting output packet signals that have been discardedand an input and output circuit designation unit for designating apacket flow to be monitored; an input discard traffic counter collectionunit for periodically obtaining a count value from said input discardtraffic count unit in the packet flow designated by said input andoutput circuit designation unit; an output discard traffic countercollection unit for periodically obtaining a count value from saidoutput discard traffic count unit in the packet flow designated by saidinput and output circuit designation unit; and a monitor data storageunit for storing each count value obtained by said input discard trafficcounter collection unit and output discard traffic counter collectionunit.
 3. A traffic monitor system for monitoring traffic in acommunications network, comprising: a plurality of circuit interfaceunits, each being associated with a respective pair of input and outputsfor a packet signal; a switch unit for connecting a packet signal inputinto a first of said circuit interface units to a second of said circuitinterface units; each of said circuit interface units having an inputtraffic count unit for counting input packet signals and an outputtraffic count unit for counting output packet signals and each of saidcircuit interface units having an input discard traffic count unit forcounting input packet signals that have been discarded and an outputdiscard traffic count unit for counting output packet signals that havebeen discarded and an input and output circuit designation unit fordesignating a packet flow to be monitored; an input traffic countercollection unit for periodically obtaining a count value from said inputtraffic count unit in the packet flow designated by said input andoutput circuit designation unit; an output traffic counter collectionunit for periodically obtaining a count value from said output trafficcount unit in the packet flow designated by said input and outputcircuit designation unit; an input discard traffic counter collectionunit for periodically obtaining a count value from said input discardtraffic count unit in the packet flow designated by said input andoutput circuit designation unit; an output discard traffic countercollection unit for periodically obtaining a count value from saidoutput discard traffic count unit in the packet flow designated by saidinput and output circuit designation unit; and a monitor data storageunit for storing each count value obtained by said input traffic countercollection unit and output traffic counter collection unit, and eachcount value obtained by said input discard traffic counter collectionunit and output discard traffic counter collection unit.
 4. The trafficmonitor system, as claimed in claim 1, wherein: said input and outputcircuit designation unit designates a packet flow to be monitored byselecting the flow from among all packet flows.
 5. The traffic monitorsystem, as claimed in claim 2, wherein: said input and output circuitdesignation unit designates a packet flow to be monitored by selectingthe flow from among all packet flows.
 6. The traffic monitor system, asclaimed in claim 3, wherein: said input and output circuit designationunit designates a packet flow to be monitored by selecting the flow fromamong all packet flows.
 7. The traffic monitor system, as claimed inclaim 1, wherein: said input and output circuit designation unitdesignates a packet flow to be monitored by sequentially anddivisionally selecting the flow to be monitored from among all packetflows.
 8. The traffic monitor system, as claimed in claim 2, wherein:said input and output circuit designation unit designates a packet flowto be monitored by sequentially and divisionally selecting the flow tobe monitored from among all packet flows.
 9. The traffic monitor system,as claimed in claim 3, wherein: said input and output circuitdesignation unit designates a packet flow to be monitored bysequentially and divisionally selecting the flow to be monitored fromamong all packet flows.
 10. The traffic monitor system, as claimed inclaim 1, further comprising a circuit utilization rate computation unitfor computing a utilization rate of the packet flow being monitoredusing an input count value or an output count value stored in saidmonitor data storage unit.
 11. The traffic monitor system, as claimed inclaim 3, further comprising a circuit utilization rate computation unitfor computing a utilization rate of the packet flow being monitoredusing an input count value or an output count value stored in saidmonitor data storage unit.
 12. The traffic monitor system, as claimed inclaim 2, further comprising a circuit discard rate computation unit forcomputing a discard rate of the packet flow being monitored using aninput discard count value or an output discard count value stored insaid monitor data storage unit.
 13. The traffic monitor system, asclaimed in claim 3, further comprising a circuit discard ratecomputation unit for computing a discard rate of the packet flow beingmonitored using an input discard count value or an output discard countvalue stored in said monitor data storage unit.